Rotary power tools such as miter saws, circular saws, radial arm saws, table saws, and the like, employ a rotary blade or saw blade comprising a generally circular, planar disk having cutting teeth that is spun by a motor to cut a workpiece. The rotary blade includes a central aperture through which the blade is clamped to the motor output drive shaft or arbor of the rotary power tool.
The process of removing and replacing a rotary blade is difficult and time consuming. Because of the forces placed on the rotary blade during the cutting operation, the blade must be securely clamped to the arbor of the rotary tool. Typically, the arbor of the rotary tool is provided with a flange against which the inner surface of the rotary blade is placed. A second flange is then placed against the outer surface of the rotary blade, and an arbor bolt is threaded into a threaded hole in the arbor through apertures formed in the rotary blade and flanges. The arbor is then held stationary (e.g., by engaging a pin with the motor shaft or using a specially designed tool) and a wrench is used to tighten the arbor bolt within the threaded hole, clamping the rotary blade between the flanges.
Consequently, it has long been desirable to provide a blade clamping assembly that allows rotary blades to be removed and replaced quickly without the use of tools such as wrenches or the like. However, to eliminate the use of tools, any such blade clamping assembly must be capable of multiplying the torque that a user is capable of applying by hand to providing sufficient axial or clamping force to the rotary blade to adequately secure the blade to the arbor.